Currently, various new communication techniques based on an internet protocol (IP) network have become hot issues under research. As for a voice over Internet protocol (VOIP) technique, analogue voice stream signals are transmitted in the IP network environment in a form of grouped data after being compressed and packaged, which has the advantages incomparable by the traditional telephone. As the communication technology has been developed rapidly, the VOIP network is displacing a public switched telephone network (PSTN), and is approved by more and more people. In consideration of security and other reasons, relevant security department or some special units usually need to intercept the internal communications over network. In the prior art, a method for service interception is realized through saving and recovering the voice streams in the PSTN communication network in the prior art, so as to intercept the PSTN voice call.
During a process of realizing the present invention, the inventor(s) finds that the prior art at least has the following problems:
The prior interception technique is applicable to the PSTN network to intercept the voice streams in the PSTN network, but it is the grouped data that is transmitted over the VOIP network, so the method for intercepting the voice streams in the PSTN network in the prior art cannot be applied to the VOIP network at all, in other words, the voice data required to be intercepted in the VOIP network cannot be effectively obtained.